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From: "Randy Brukardt" <randy@rrsoftware.com>
Newsgroups: comp.lang.ada
Subject: Re: Discriminant of a limited type object
Date: Wed, 28 Feb 2018 17:10:22 -0600
Organization: JSA Research & Innovation
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 <p74lj6$ls3$1@franka.jacob-sparre.dk> <p74nge$1oto$1@gioia.aioe.org>
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Xref: reader02.eternal-september.org comp.lang.ada:50723
Date: 2018-02-28T17:10:22-06:00
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"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message 
news:p74nge$1oto$1@gioia.aioe.org...
...
> The problem is passing state between calls to the function. The code in 
> mind is a loop over array elements. The loop body gutted and its parts 
> moved into the function.
>
>    A : T (1..N);
> begin
>    for Index in A'Range loop
>       do-init of A (Index)
>    end loop;
>
>         |
>         V
>
>    Index : Positive := 1;
>    function F return Element is
>    begin
>       Index := Index + 1;
>       return do-init of A (Index - 1);
>    end F;
>    A : T (1..N) := (others => F)
>
> Quite ugly. In the end I decided to flatten record variants and make the 
> discriminant a plain record member. The memory loss is not big enough to 
> justify the code above.

Ada 2020 has you covered:

    function F(Index : Natural) return Element is
    begin
       return do-init of A (Index - 1);
    end F;
    A : T (1..N) := (for I in 1 .. N  => F(I));

Note the new iterator choice in the aggregate.

                                           Randy.